Global ocean alkalinity measured from space.
according to research published in the journal Environmental Science and Technology. Currently, scientists must rely on measurements taken from research vessels and sampling equipment deployed in oceans to determine acidity — which rises as the oceans absorb CO2 from the atmosphere — but this approach is expensive and geographically limited. The new techniques use satellite-mounted thermal cameras to measure ocean temperature and microwave sensors to measure salinity. Together these measurements can be used to assess ocean acidification more quickly and over much larger areas than has been possible before.

Blessed with lots of sun and keen to cut its reliance on imported oil, Hawaii has moved to the forefront of residential solar installations in the U.S. But financial and technical hurdles are slowing the state’s drive to generate 40 percent of its electricity from renewable energy by 2030.
BY ERICA GIES

The Martian limb (that is, the observed ‘edge’ of the planet) represents a unique window into the complex atmospheric phenomena occurring there. Clouds of ice crystals (CO2 ice or H2O ice) have been observed numerous times by spacecraft and ground-based telescopes, showing that clouds are typically layered and always confined below an altitude of 100 kilometres; suspended dust has also been detected at altitudes up to 60 kilometres during major dust storms. Highly concentrated and localized patches of auroral emission controlled by magnetic field anomalies in the crust have been observed at an altitude of 130 kilometres. Here we report the occurrence in March and April 2012 of two bright, extremely high-altitude plumes at the Martian terminator (the day–night boundary) at 200 to 250 kilometres or more above the surface, and thus well into the ionosphere and the exosphere. They were spotted at a longitude of about 195° west, a latitude of about −45° (at Terra Cimmeria), extended about 500 to 1,000 kilometres in both the north–south and east–west directions, and lasted for about 10 days. The features exhibited day-to-day variability, and were seen at the morning terminator but not at the evening limb, which indicates rapid evolution in less than 10 hours and a cyclic behaviour. We used photometric measurements to explore two possible scenarios and investigate their nature. For particles reflecting solar radiation, clouds of CO2-ice or H2O-ice particles with an effective radius of 0.1 micrometres are favoured over dust. Alternatively, the plume could arise from auroral emission, of a brightness more than 1,000 times that of the Earth’s aurora, over a region with a strong magnetic anomaly where aurorae have previously been detected. Importantly, both explanations defy our current understanding of Mars’ upper atmosphere.

Risk of future prolonged drought in the Southwest
a new study forecasts, and the drought will be worse than anything seen in modern history or even during ancient so-called "megadroughts." Many studies have predicted that the Southwest could dry due to human-induced climate change, but this is the first to say that such drying could exceed the worst conditions of the distant past. The impacts of such a future drought would be devastating, the researchers say, given the region’s much larger population and heavy reliance on water and other natural resources. “The surprising thing to us was really how consistent the response was over these regions, nearly regardless of what model we used or what soil moisture metric we looked at,” said lead author Benjamin I. Cook, a researcher with Columbia University and NASA.

Researchers with the U.S. Geological Survey are using thermal video cameras to study how mange is affecting

Thermal image of a wolf with mange on its legs.
wolves in Yellowstone National Park, as shown in this video. Mange is a highly contagious skin disease caused by mites that burrow into the skin of dogs and wolves, causing infections, hair loss, irritation, and intense itching. The urge to scratch can be so overwhelming that the wolves neglect resting and hunting, researchers say, leaving them vulnerable to hypothermia, malnutrition, and dehydration, which can eventually lead to death. Thermal imagery allows scientists to document the extent of hair loss and the actual loss of heat associated with different stages of infection. Red patches on a wolf's legs, as shown in this image, indicate rapid heat loss caused by mange.

Once abundant in the rivers of eastern North America, the Atlantic sturgeon has suffered a catastrophic crash in its populations. But new protections under the U.S. Endangered Species Act are giving reason for hope for one of the world’s oldest fish species.
BY TED WILLIAMS

Geoengineering, an experimental series of technologies aimed at counteracting the effects of climate change, could potentially diminish political polarization over global warming, according to new research. Roughly 3,000 participants in a study displayed more open-mindedness toward evidence of climate change and more agreement on the significance of such evidence after learning about geoengineering technologies, according to a study conducted by researchers at Yale and other universities. Participants became more polarized when they were told that curbing climate change would require reducing greenhouse gas emissions, the researchers report. The findings come after a report this week from the U.S. National Research Council recommended limited government-sponsored research into the use of sulfate aerosols, a potential geoengineering strategy known as albedo modification.

With the steady retreat of sea ice in the Arctic Ocean opening up vast areas of this long-frozen marine basin, a key resource

A Russian fishing vessel trawls the Arctic Ocean.
issue is now emerging: the future of fisheries, especially in central Arctic waters. What species are migrating into the region as sea ice disappears? And could the heart of the Arctic Ocean sustain a commercial fishery in the coming decades? These issues were central to a discussion at a recent conference on the fisheries of the central Arctic Ocean. With more southerly fish species migrating into warmer and increasingly ice-free regions of the Arctic Ocean, officials from the U.S. and Canada say it’s important to negotiate an international agreement on fishing before allowing fisheries to open. Read the article.

Many experiments have probed the mechanisms by which transplanted stem cells give rise to all the cell types of the blood, but it emerges that the process is different in unperturbed conditions. See Letter p.542

Haematopoietic stem cells (HSCs) are widely studied by HSC transplantation into immune- and blood-cell-depleted recipients. Single HSCs can rebuild the system after transplantation. Chromosomal marking, viral integration and barcoding of transplanted HSCs suggest that very low numbers of HSCs perpetuate a continuous stream of differentiating cells. However, the numbers of productive HSCs during normal haematopoiesis, and the flux of differentiating progeny remain unknown. Here we devise a mouse model allowing inducible genetic labelling of the most primitive Tie2+ HSCs in bone marrow, and quantify label progression along haematopoietic development by limiting dilution analysis and data-driven modelling. During maintenance of the haematopoietic system, at least 30% or ∼5,000 HSCs are productive in the adult mouse after label induction. However, the time to approach equilibrium between labelled HSCs and their progeny is surprisingly long, a time scale that would exceed the mouse’s life. Indeed, we find that adult haematopoiesis is largely sustained by previously designated ‘short-term’ stem cells downstream of HSCs that nearly fully self-renew, and receive rare but polyclonal HSC input. By contrast, in fetal and early postnatal life, HSCs are rapidly used to establish the immune and blood system. In the adult mouse, 5-fluoruracil-induced leukopenia enhances the output of HSCs and of downstream compartments, thus accelerating haematopoietic flux. Label tracing also identifies a strong lineage bias in adult mice, with several-hundred-fold larger myeloid than lymphoid output, which is only marginally accentuated with age. Finally, we show that transplantation imposes severe constraints on HSC engraftment, consistent with the previously observed oligoclonal HSC activity under these conditions. Thus, we uncover fundamental differences between the normal maintenance of the haematopoietic system, its regulation by challenge, and its re-establishment after transplantation. HSC fate mapping and its linked modelling provide a quantitative framework for studying in situ the regulation of haematopoiesis in health and disease.

Darwin’s finches, inhabiting the Galápagos archipelago and Cocos Island, constitute an iconic model for studies of speciation and adaptive evolution. Here we report the results of whole-genome re-sequencing of 120 individuals representing all of the Darwin’s finch species and two close relatives. Phylogenetic analysis reveals

Microcapsules containing a liquid carbonate solvent could capture carbon dioxide from power plants more efficiently than existing methods.Currently, CO2 is captured at power plants by passing the flue gas over a solution of liquid monoethanolamine. The liquid is corrosive, forms toxic by-products